1. Field of the Invention
The present invention relates to a leg mechanism for a robot and in particular relates to a leg mechanism for a planetary exploration robot or extreme operations robot comprising a plurality of legs that are capable of three-dimensional movement and are capable of being independently driven and controlled, which is capable of self-righting when overturned and which facilitates take-off and landing on uneven ground.
2. Description of the Related Art
Since in many cases the shape condition of the surface is unknown when landing on the surface of the moon, Mars or other planets, it may be assumed that a planetary landing vehicle used to land on for example the lunar surface and collect surface materials etc may be unable to maintain its normal posture and may overturn on landing. Also, when returning, it is considered to be necessary to support the return vehicle in the normal posture for purposes of the rocket jet. If the landing vehicle is regarded as an unmanned robot, it is required that the legs of this robot should be multi-functional legs (arms) that are capable not merely of being employed during landing and take-off but also, due to the need for weight reduction, of also serving for walking, running and handling operations. More specifically, functions that would ideally be demanded include a function of being able to right itself under its own power after being overturned, the ability to walk, the ability to run with wheels, the ability to mitigate the impact of landing, the ability to function as hands during collection of materials or other operations, the ability to hold heavy objects, the ability to maintain posture, the ability to freely direct a camera or sensor mounted on these legs in a desired direction and a self-repairing or compensating function in the event of malfunction. Apart from planetary exploration as described above, a robot having these functions could also be applied terrestrially as an extreme operations robot etc for performing taks and/or recovery in dangerous topography which it is difficult for human beings to enter directly, caves, deserts, volcanoes, the poles or under the sea or at the seabed. However, such a multi-functional robot has conventionally not yet been proposed.